An access-control list (“ACL”) is a well known security mechanism that comprises a list that can be used to limit access to data files and program files to one or more people listed in the ACL. For example, a user “John Smith” or a named program may be listed in an ACL, along with a named data file or a named program file, as being authorized to access the named data file or the named program file. If John Smith or the named program requests access to the file, the operating system checks the ACL to determine if John Smith or the named program is authorized to access the file.
While this type of ACL is secure, it must be updated every time a file is added to the system in order to add an entry in the ACL for the new file and to indicate which entities are authorized to access the new file.